Fishery

Studies on breeding and larval rearing of Labeo calbasu (Hamilton) under mid hill altitudinal region of Meghalaya.

Successful spawning of pond reared Labeo calbasu was observed at different temperatures (21-26°C) and high altitude (900m) by using both Carp pituitary extract, Ovatide and Ovaprim as stimulating agents.
Carp Pituitary Extract was also found suitable for breeding with a dose ranging from 4 to 5 mg/kg in male. In female, a first dose of 3 – 4 mg/kg and a second dose of 8 to 10 mg/kg were found effective.
Ovaprim was found suitable with a dose ranging from 0.3 to 0.5 ml/kg in male, while females required 0.6 to 0.8 ml/kg. Ovatide was found effective for breeding with a dose ranging from 0.3 to 0.4 ml/kg in male and 0.5 – 0.7 ml/kg in female.

Studies on artificial propagation of Chocolate Mahseer, Neolissocheilus hexagonolepis

Captive breeding of chocolate mahseer was successful in ICAR Complex fish farm at Barapani. The source of broodstock was Umiam river.
The female brood fish weighed 200-300g, while the males were of 50-100g size.
Incubation was done in enamel trays with mild aeration and the incubation period ranged from 80-84 hours. Percentage of hatching was 85 and the yolk-sac absorption in larvae was complete 6 days after hatching and the larvae were subsequently maintained on planktonic diet for a period of one month.
The fry were subsequently reared in cement cisterns up to fingerling size and the fingerlings were raised in ponds, where they attained about 150 grams in 1 year and matured in 1+ year of age in pond conditions.

Studies on the Breeding of Indigenous Magur, Clarias batrachus

The indigenous magur, Clarias batrachus was bred successfully in ICAR Complex fish farm at Barapani. The brood fishes were induced using ovaprim @ 0.75ml/kg for males and 2.0ml/kg for females.
Eggs were stripped out 20 hours after injection. During the same time, the testis was removed from males and macerated. The ova and milt were mixed thoroughly using a feather for fertilization and the eggs were incubated in glass jar hatchery as well as in enamels trays.

Standardization of suitable concentration of activating solution (NaCl Sol.) for activation of sperm motility in Chocolate Mahseer (Neolosochilous hexagonolepis)

A study was undertaken to evaluate different concentrations of NaCl on activation of sperm motility in Chocolate Mahseer.
The concentration of NaCl studied was 10, 25, 50, 75, 100 and 200 mM. Fresh milt was collected from mature Chocolate Mahseer (n=10) as per the standard hand stripping method, during October to November months.
Fresh milt was divided into two parts; part one was used for sperm activation studies while part two was centrifuged and sperm and seminal plasma were separated for protein profile studies. Part one of each milt was split into six sub parts and extended in 10, 25, 50, 75, 100 and 200 mM NaCl solution.
The parameters studied were sperm motility and latency period. Results revealed that maximum sperm were non motile in fresh milt. Upon mixing different molalities of activating solution the sperm motility was activated.
Among the different concentration of activating solution, 50mM NaCl was found to be the best concentration for activation of sperm motility. The latency period in this group was 1 to 2 seconds and the percentage of sperm motility was more than 80%. In 75mM NaCl solution added group oscillatory and circular motion of sperm was very much evident.
There were no motile sperm in the concentration of activating solutions containing more than 100mM NaCl. Sperm membrane and seminal plasma protein profile studies are in progress. It may be inferred from the result of the present study, that 50 mM NaCl can be used for activation of sperm motility in Chocolate Mahseer.

Effect of self-recruiting native species in composite fish culture

Incorporation of native fishes like Amblypharyngodon mola, Notopterus notopterus, Puntius conchonius, and Puntius sophore in composite fish culture. Mature fishes were stocked along with Catla catla, Labeo rohita, Cirrhinus mrigala, Ctenopharyngodon idella, Cyprinus carpio in the ratio of 2:1:1:2:1 in ponds of 0.1 ha.
The stocking density was 7000 fingerlings/ha excluding the native fishes.
The experiment with Puntius conchonius and P. sophore was failed. Puntius conchonius was failed to breed in pond condition. P. sophore could breed but significant population of next generation was not found rather it acted as store house of various parasites including 3 species of monogenetic trematodes and 5 species of myxosporidian parasites.
The result showed significant increase (10.1%) in the total fish production without affectiong the performance of the other species in mola and kanla based composite culture experiment. Due to self-recruiting nature the second year of auto-stocking the over crowing of mola was observed.
So periodical harvesting (once in 3 months) is necessary to have netter production of carps and better total output. Notopterus can be harvested annually leaving 10-20 fishes for next year stocking. The technology was transferred to 55 farmers (30 in Bishramgang area and 25 in and around Lembucherra with supply of stocking material for indigenous fish). Aquaculture of native fish A. mola:

Studies on parasitic diseases of fishes

A preliminary survey was conducted in the west Tripura district for identifying the parasitic infection of the fishes in the aquaculture system.
A total of 187 fishes were examined for metazoan parasites. 336 parasites and 386 myxosporidian cysts were collected and identified upto family level. The incidence of protozoans and the intensity of infection were highest in case of helminthes (45.5 and 10.2% respectively).
Incidence and intensity of infection was lowest in crustacean parasites. 3 major group of protozoans found infecting are-myxosporidian, microsporidian and trichodina spp. In helminthes, both Dactylogyrus and Gyrodactulus were found infecting the fishes. Snail populations were common in most of the ponds but the infection of digeneans was very less. Only the meta cercaria of Centrocestus formosanus was present.
Infection by fish leech was found only in one instance. Nematode infection was found in C. mrigala and Acanthocephalan infection was confined to C. catla. Cestodes plerocercoids were collected from mrigala and P. javonicus. Ergasilus and Neoergasilus were found commonly in fishes. Catlaphila was found in catla only. Lernaea was found in mrigala.
Nature and infection of parasites: monogenean and digenean infection did not show much seasonal fluctuation. Copepod infection was found influenced by seasonal fluctuation especially for number and species.
The genus Neoergasilis flourish during winter and other ergasilids were found very rare during this period. The copepods which infect the nasal cavities and snout regions were also found less during winter months. Chinese carps were found resistant to parasitic infections than IMCs.

Rearing system	Weight parameters				Length parameters
Rearing system	Absolute Growth (g)±SD	Growth Increment (g/fish/day)	Specific Growth Rate (%)	Total Weight Gain (g/fish)	Absolute Length (cm)±SD	Length Increment (cm/fish/day)	Specific Length Rate (%)	Total Length Gain (cm/fish)
Cage	2.57±2.07	0.04	0.03	4.96	1.9±0.9	0.03	0.01	0.6
Aquarium	0.68±0.12	0.01	0.06	0.68	1.4±0.4	0.02	0.007	0.06

Preliminary trial on paddy-cum-fish culture under integrated farming system

A paddy-cum-fish culture trial was undertaken in an area of 0.24 ha for 120days. Total area was divided in to four plots of each measuring 0.06 ha. A middle trench with an area of 15 m2 and 1 m deep was excavated for shelter of fishes in all the four plots.
This study was conducted to optimize the stocking density and to observe their growth in a zero input paddy cum fish culture system in a low-lying paddy field. Common carp fingerlings were released at different stocking densities viz. (T-1) 150, (T-2) 120, (T-3) 90 and (T-4) 60 randomly in to the four experimental units. T-4 was considered as control group. Before releasing fingerlings their average length and weight were recorded (Avg. Length = 9.7 cm and Avg. Weight= 16.5 g.).
Monthly sampling was done to find out their health condition and their increment in growth. At the end of fourth sampling, data were analyzed and it was found that the difference in their growth rate in the first two months were not significant where as in the third month onwards there was a significant growth difference.
In the control group, the growth was comparatively better than other three experimental groups. From the above experiment it can be inferred that the stocking density of 60 fingerlings per 0.06 ha (1000 Nos. FL/Ha) is ideal for paddy cum fish culture in the low-lying paddy cum fish culture in present condition.

Growth performance of gold fish, Carassius auratus in aquarium and cage

The growth performance of 72 days old hatchlings were evaluated under cage culture and conventional aquarium conditions.
The low-cost cage (L: 2.84´B: 1.13´H: 1.07 mt) was fabricated with bamboo and nylon net. The cage was placed submerged inside a pond. Fishes with initial mean body weight of 0.52±0.18g and mean body length of 3.19±0.58cm were stocked in the cage. In the other hands, fishes with initial mean body weight of 0.02±0.17g and mean body length of 2.17±0.71cm were earlier stocked in aquarium.
The fishes in cage were allowed to feed on natural foods only, whereas in aquarium, fishes were partially supplemented with rice polish along with the natural foods (planktons).
Samplings were done on 35 and 70 days from the beginning of trial. The study observed that, gold fish reared in cages attained better growth rate and developed bright coloration faster than the aquarium-reared ones. The details of growth attainment after 70 days of rearing are presented in Table.

Kinetic of enzyme alkaline phosphatase in endangered Chocolate mahseer N. hexahonolepis and its nutritional status

The enzyme alkaline phosphatase is widely distributed in nature and is characterized by a high pH in the ecosystem.
The physiological role of alkaline phosphatase remains uncertain except for a role in bone mineralization and as stress indicator. In the present study, attempt was made to assess the activity of alkaline phosphatase in different organs of Chocolate mahseer and its significance in counteracting stress due to captivity or confinement.
Further, the study also investigated the nutritional profile of Chocolate mahseer, which is considered as an endangered species.
The study revealed that, the activity of alkaline phosphatase is more in kidney followed by liver, intestine and muscle. The increased activity in kidney may be due to the fact that, the phosphatase are very important for regulation of various metabolic process that occurs by phosphorylation and dephosphorylation with kinase, especially during stress condition to meet the energy requirement in the animal.
Further, the Chocolate mahseer is found to be rich in crude protein, calcium and phosphorus.

Table: Nutritional profile of Chocolate mahseer, N. hexagonolepis

Nutritional parameters	Percentage
Crude Protein (DW)	76.78
Ether Extract	06.48
Dry Matters	31.89
Crude Fibre	00.35
Total Ash	07.50
Calcium	01.03
Phosphorus	01.95
Cholesterol	170 mg/dl

Study on pathogenic fungi in fish culture ponds located at mid-hill altitude

For fungal disease characterization, live infected fish (Indian major carps; n= 10 per species) were randomly collected from farm complex of ICAR Complex, Barapani during 2009-2010. Samples from each infected pond were collected after 2, 6, 10 and 20 weeks from the onset of disease.
The cotton-wool appeared on the body surface of fishes were removed by sterile incubating loop and incubated in Sabauravd’s dextrose agar plates and store at 22-30°C for 5-10 days inside incubator. The plates were observed everyday at 1000Hrs for growth.
For identification of fungus, the cultures were subjected to Lactophenol Cotton Blue stain and were examined under a microscope at magnifications between 10-100X. The microbiological test observed that, the predominant pathogen was Saprolegnia sp.
Interestingly, the occurrence of fungal pathogen was directly correlated with the lowest water temperature (8-10°C), pH (4-5) and dissolved oxygen (3-5ppm).

Nutritional profiling of commercially important food fishes

A database on nutritional facts of fishes that are either native to the region or introduced from other states or country will give an idea to the consumers and/or dieticians a preference to choose a fish that is nutritionally sound.
Nutritional profile of some of the important cultivable fish species are presented in Table below.

Fish species	Moisture (%)	Protein (% DW)	Lipid (%)	Ash (%)
Puntius sphore	62.92	44.82	35.07	15.78
Anabas testidinius	55.22	45.26	32.05	19.92
Channa striatus	67.28	54.44	15.21	22.89
Chanda nama	75.87	52.33	26.72	15.30
Labeo bata	70.98	53.73	31.52	10.46
Amblipharyngodon mola	77.02	55.85	20.55	16.94
Wallago attu	72.74	61.22	25.53	4.48
Xenotondon cancilla	74.52	60.64	17.63	15.30
cyprinus carpio	76.03	59.10	18.08	13.96

Captive breeding of Amur- Common carp

A genetically improved variety of Common carp –Amur (Hungarian strain) has been introduced for the first time in the ICAR NEH Region fish farm, Barapani, Meghalaya in early 2010.
The breeder’s seeds of this variety were procured from the Fisheries Research and Information centre of Karnataka Veterinary, Animal and Fisheries Sciences University, Bangalore. Initial trial on this variety had shown encouraging results. In a culture period of six months, the fish attained an average weight of 300 g under mono culture condition at the farm complex of the institute.
The breeder’s seeds of initial average weight 14.5 g reared under mid altitude condition at the institute fish farm complex attained maturity in about 14 months period. A few fishes attained a Maximum weight of 1.5 Kgs in a culture period of 14 months.
Male matured earlier than the female. The first breeding trial with this new variety was conducted successfully in March’2011 when the atmospheric temperature varied between 160C to 18.3 0 C.
The fertilized eggs took about 78 to 83 hours to hatch. Water temperature ranged between 19 0 C to 22.8 0 C while water pH varied between 6.5 to 6.8.

Fish farming in rice field

Rice - fish is the basic diet for most people of northeast India. A low lying area connected with a perennial stream was selected jointly with the Soil science division of the institute for conducting the experiment. Under mid hill condition, Common carp in rice field (plot size: 61 X 12 m=732 Sq.mt) yielded encouraging results.
The paddy plot was designed with perimeter canal (size: 1 m width & 0.75 m depth) and a centre pond (size: 5m Diameter & 0.75 m Depth) for rearing only Common carp, Cyprinus carpio at a stocking density of 5,000 nos/ha. Common carp seeds of average size 7 cm in length and 6 g in weight were introduced after 21 days of paddy plantation on 10.08.2010. In a rearing period of 237 days a production of 683 kg of common carp per hectare could be obtained without supplementary feeding.
An average fish growth of 177.5 g was recorded during the period, while the maximum growth of an individual fish was 435 g.

Fry nursing of Golden mahseer, (Tor putitora, Ham )- An endangered species in pond based cage culture system:

Golden mahseer, Tor putitora is one of the most important fish species of the Northeast especially in the hill states. However, the population of this important indigenous fish species has been reduced to a great extent over the years due to several factors.
Since the species now constitutes a negligible fishery of the hill streams and rivers, it has been categorized under the endangered fish species. Recently, an effort has been made to rear the juveniles of this species at the fish farm complex of the institute. The seeds of Golden mahseer was provided by the Directorate of Cold water Fisheries Research, ICAR, Bhimtal , Uttarakhand.
Golden mahseer Juveniles of average size 2.36 cm was stocked in a 1 cubic meter low-cost bamboo cage at a stocking density of 100 nos per square meter in the month of september’2010. The cage of size 1X1x1 m was fabricated with bamboo and nylon net material which was fixed in a pond with the help of bamboo poles for evaluation of survivality and growth over a period of 60 days from September to November’2010.
The experiment recorded 70 % survival and a growth increment 2.39 cm in terms of length and 11 g in terms of weight under pond based cage culture system . During the study period water temperature varied between 17 – 28°C while average water pH was 7.

Thermal tolerance of potential native fish species Brachidanio rerio and Danio dangila acclimatized to four different temperatures. (Under NICRA)

Recent studies have shown that exposure to warm water can adversely affect the growth, survibility and reproduction of fishes inhabiting in the hill streams.
This study was designed to determine the species specific variation in thermal tolerance and metabolic activity, critical thermal maximum (CTMax) and lethal thermal maximum (LTMax) of Danio dangila and Brachidanio rerio adults acclimatized at four temperatures.
For this purpose, fish were reared continuously at constant temperatures of 20, 25, 30 and 35°C for 45 days. The results implicate CTMax (36.4±0.05, 37.2±0.04, 38.7±0.03, 39.8±0.01); LTMax (39.8±0.03, 40.4±0.02, 41.2±0.06, 42.2±0.03), increased significantly (p<0.05) in B. rerio with increasing acclimation temperatures. Similarly, CTMax (36.2±0.02, 37.7 ±0.31, 39.6±0.07, 40.9±0.10); LTMax (38.1±0.08, 39.8±0.06, 40.0±0.07, 41.1±0.04) increased significantly (p<0.05) in D. dangila with increasing acclimation temperatures.
Inter species specific variation (between B. rerio and D. dangila) was evident at 30 and 35°C. Oxygen consumption rate increased (p<0.05) with increasing temperatures in both the species. However, temperature quotient (Q10) was more in B. rerio (1. 52) in comparison to D. dangila (1. 43).
Overall results suggest that B. rerio is more thermal tolerant and show better adaptation in comparison to D. Dangila.

Feed utilization and reproductive competence of H. fossils males reared in comparatively high temperature (Under NICRA)

In general, fishes cannot maintain a constant body temperature like mammals do. Their body is exactly the same temperature as the water they are living in.
Fishes can live in very cold or very hot water, but each species has a range of preferred temperatures. Most fish can’t survive in temperatures too far out of this range. When fish encounter water that is too cold for them, their metabolic activities slow down and become lethargic.
On the contrary, as the surrounding water warms up, metabolic activities speed up and they digest food more rapidly, grow more quickly, and eventually have more energy for reproduction. But fish need more food and more oxygen to support this higher metabolism.
On this backdrop, the current experiment was conducted to study the feed utilization efficiency by H. fossilies at ambient (17±0.5°C) and comparatively higher water temperature (32±0.5°C).
Experimental feeds were prepared using viscera of pig and goat and were fed twice daily at 5% body weight. The growth parameters and gonado-somatic index was recorded at 15 days interval from the beginning of experiment.
The study implicates goat viscera based feed utilization is better at higher temperature (32±0.5°C) with significant increased in GSI than other tested feeds at same and/or lower temperature (see Table below).

Table: Experimental design, variation in weight gain (g) and GSI (%) by feeding 3 experimental diets to the H. fossilis at elevated and ambient water temperature.

FISHERIES